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1.
Metal Derivatives of Molecular Compounds. VII. Bis[1,2-bis(dimethylamino)ethane-N,N′]lithium Disilylphosphanide — Synthesis and Structure Crystalline lithium phosphanides studied so far show a remarkably high diversity of structure types dependent on the ligands at lithium and the substituents at phosphorus. Bis[1,2-bis(dimethylamino)ethane-N,N′]lithium disilylphosphanide ( 1 ) discussed here, belongs to the up to now small group of compounds which are ionic in the solid state. It is best prepared from silylphosphane by twofold lithiation with lithium dimethylphosphanide first and subsequent monosilylation with silyl trifluoromethanesulfonate, followed by complexation. As found by X-ray structure determination (wR = 0.038) on crystals obtained from diethyl ether {monoclinic; space group P21/c; a = 897.8(1); b = 1 673.6(2); c = 1 466.8(1) pm; β = 90.73(1)° at ?100 ± 3°C; Z = 4 formula units}, the lithium cation is tetrahedrally coordinated by four nitrogen atoms of two 1,2-bis(dimethylamino)ethane molecules. Characteristic parameters of the disilylphosphanide anion are a shortened average P? Si bond length of 217 pm (standard value 225 pm) and a Si? P? Si angle of 92.3°.  相似文献   

2.
Metal Derivatives of Molecular Compounds. VIII. catena-Poly[(2,5,8-trioxanonane-O2,O5) lithium-methylphosphanide] — a Compound with a meso-Helix Structure Studies of Fritz et al. [10] showed methylphosphane to be lithiated at ?60°C in 1,2-dimethoxyethane or bis(2-methoxyethyl) ether solution by stoichiometric amounts of lithium n-butanide in n-hexane. After removing the hydrocarbons almost completely by distillation and cooling the solutions to ?60°C again, colourless square crystals of (1,2-dimethoxyethane-O,O′)lithium ( 1 ) and (2,5,8-trioxanonane-O2,O5)lithium methylphosphanide ( 2 ) precipitate. As shown by an X-ray structure determination (monoclinic, P21/n; a = 805.5(1); b = 1820.6(2); c = 851.5(1) pm; β = 116.76(1)° at ?100 ± 3°C; Z = 4 formula units; R = 0.034) complex 2 forms a polymer which has the shape of an up to now scarcely noted meso-helix. Four-coordinated lithium is bound to two phosphorus (P? Li 252.9 and 253.2 pm; P? Li? P 131.8°; Li? P? Li 132.1°) and to two oxygen atoms (Li? O 203.9 and 206.8; O …? O 270.7 pm; O? Li? O 82.5°) of the inherently tridentate 2,5,8-trioxanonane ligand. As compared to the standard value (185 pm) the P? C distance (187.4 pm) is slightly lengthened. Structure determinations of (2,5,8-trioxanonane-O2,O5,O8) lithium 1-(phenylsulfonyl)alkyl compounds published some years ago [26, 27], allow a comparison of molecular parameters characteristic for the twofold or threefold coordinating chelate ligand.  相似文献   

3.
Metal Derivatives of Molecular Compounds. IV Synthesis, Structure, and Reactivity of Lithium [Tris(trimethylsilyl)silyl]tellanide · DME Lithium tris(trimethylsilyl)silanide · 1,5 DME [3] and tellurium react in 1,2-dimethoxyethane to give colourless lithium [tris(trimethylsilyl)silyl]tellanide · DME ( 1 ). An X-ray structure determination {-150 · 3·C; P21/c; a = 1346.6(4); b = 1497.0(4); c = 1274.5(3) pm; β = 99.22(2)·; Z = 2 dimers; R = 0.030} shows the compound to be dimeric forming a planar Li? Te? Li? Te ring with two tris(trimethylsilyl)silyl substituents in a trans position. Three-coordinate tellurium is bound to the central silicon of the tris(trimethylsilyl)silyl group and to two lithium atoms; the two remaining sites of each four-coordinate lithium are occupied by the chelate ligand DME {Li? Te 278 and 284; Si? Te 250; Li? O 200 pm (2X); Te? Li? Te 105°; Li? Te? Li 75°; O? Li? O 84°}. The covalent radius of 154 pm as determined for the DME-complexed lithium in tellanide 1 is within the range of 155 ± 3 pm, also characteristic for similar compounds. In typical reactions of the tellanide 1 [tris(trimethylsilyl)silyl]tellane ( 2 ), methyl-[tris(trimethylsilyl)silyl]tellane ( 4 ) and bis[tris(trimethylsilyl)silyl]ditellane ( 5 ) are formed.  相似文献   

4.
Metal Derivatives of Molecular Compounds. V. Synthesis and Structure of Hexakis{lithium-[tris(trimethylsilyl)silyl]tellanide}—Cyclopentane (1/1) . Lithium [tris(trimethylsilyl)silyl]tellanide—DME (1/1) [1 b] prepared from lithium tris(trimethylsilyl)silanide—DME (2/3) [3] and tellurium, reacts with hydrogen chloride in toluene to form [tris(trimethylsilyl)silyl]tellane ( 1 ) [1 b]. Subsequent metalation of this compound with lithium n-butanide gives lithium [tris(trimethylsilyl)silyl]tellanide ( 2 ) free of coordinating solvent. Pale yellow crystals are obtained from cyclopentane solution. An X-ray structure determination {P1 ; a = 1 558.5(7); b = 1 598.4(8); c = 1 643.5(6) pm; α = 117.64(4); β = 91.63(3); γ = 117.19(3)°; Z = 1; R = 0.032} shows them to be the (1/1) packing complex ( 2 ′) of hexakis{lithium-[tris(trimethylsilyl)silyl]tellanide} and disordered cyclopentane molecules —{Li? Te? Si[Si(CH3)3]3}6 · C5H10.  相似文献   

5.
Homo- and Heteroleptic Zinc Arsanides — Syntheses and Structure Bis(trimethylsilyl)arsane reacts with dialkylzinc ZnR2 (R = Me, Et, CH2SiMe3) in the stoichiometric ratio of 1 : 1 in hydrocarbons to the heteroleptic alkyl zink bis(trimethylsilyl)arsanides. The steric demand of the alkyl substituent enforces the oligomerisation degree of two or three. Diethylzinc and two equivalents of HAs(SiMe3)2 yield dimeric zinc bis[bis(trimethylsilyl)arsanide]. Methyl zinc bis(trimethylsilyl)arsanide crystallizes as a trimer with a six-membered Zn3As3-cycle in the twist-boat conformation {orthorhombic, P212121, a = 1 015.3(1), b = 1 887.6(4), c = 2 272.9(4) pm, Z = 4}. The molecule of ethyl zinc bis(trimethylsilyl)arsanide is built similar in the solid state {monoclinic, P21/n, a = 1 220.2(4), b = 1 889.0(6), c = 1 968.5(6) pm, β = 90.24(1)°, Z = 4}. However, zinc bis[bis(trimethylsilyl)arsanide] separates due to the steric demand of the terminal (Me3Si)2As-ligand as a dimer in the triclinic space group P1 {a = 967.8(2), b = 1 088.5(2), c = 1 238.1(2) pm, α = 92.41(1), β = 105.20(1), γ = 105.05(1)°, Z = 2}. The endocyclic zinc-arsenic distances vary only slightly around 248 pm, but the exocyclic one is with a value of 238 pm drastically shorter. The Zn? C bond lengths with values around 197 pm lie in the characteristic region for zinc with the coordination number of three.  相似文献   

6.
Synthesis and Structure of Cs11[(WN2,5O1,5)2](N3)2, a Cesium Oxo Nitrido Monotungstate(VI) Azide Cs11[(WN2,5O1,5)2](N3)2 results from the reaction of a mixture of CsNH2, W and WO3 at 620 °C in autoclaves. It crystallizes monoclinic in the space group C2/m with the lattice parameters a = 12.421(4) Å, b = 11.568(6) Å, c = 10.516(4) Å, β = 118.71(3)° and Z = 4. The crystal structure is built up by isolated tetrahedra [WX4] with X = N, O, which are connected by cesium cations. Between the cesium ions lie azide ions separated from the anions [WX4]. The tungsten atoms and azide ions together build up the motif of a distorted arrangement of the CsCl structure type.  相似文献   

7.
Synthesis and Characterization of Tetralithiumpentaoxoselenate(VI) Pure Li4SeO5 was prepared by solid state reaction at 500 °C from a mixture of Li2O and Li2SeO4 in silver crucibles. The crystal structure was solved and refined with x‐ray powder methods (profile matching, C2/c, a = 873.3(1), b = 572.5(1), c = 783.6(1) pm, β = 98.29(1)°, Rp = 0.052, Rwp = 0.066). Li4SeO5 contains novel SeO54– anions, which form slightly distorted trigonal bipyramids. All ions are coordinated by 5 ligands in the shape of trigonal bipyramidal polyhedra, according to the formula Li4[5]Se[5]O5[5]. From the empirical formula and the coordinaton environments, it is clear that this is an order variant of the A[5]B[5] structure type, that was found in the system NaCl by global optimisation methods. The crystal structure is consistent with spectroscopic data (IR, Raman, NMR). The ionic conductivity (σ = 3.34 10–5 Ω–1 cm–1 at 340 °C) of the compound was determined with impedance measurements.  相似文献   

8.
Chemistry of Polyfunctional Molecules. 124. Silver(I) Complexes Containing the Ligands Bis(diphenylphosphanyl)amine, -amide and Tris(diphenylphosphanyl)amine Bis(diphenylphosphanyl)amine HN(PPh2)2 ( 1 ) reacts with AgCl to the complex HN(PPh2AgCl)2 ( 5 ) for which in the solid state the cluster structure Ag4Cl4[HN(PPh2)2]2 is assumed. Reaction of 5 with LiN(PPh2)2 ( 2 ) gives the known [N(PPh2AgPh2P)2N] ( 8 ) and the new complex [Ag(μ—Ph2PNPPh2)2(μ—Ph2PNHPPh2)Ag] · dioxane ( 7 · dioxane). The compound 7 · dioxane has been characterized by X-ray diffraction. The molecules are found to contain a bicyclo[3.3.3]undecane-type structure with trigonal planar coordinated silver atoms, which are separated by 281,6(1) pm. The dioxane is bound via H-bridge bond to the NH group of the coordinated HN(PPh2)2. Treatment of 8 with ClPPh2 yields N(PPh2AgCl)3 ( 12 ), which has also been obtained by the reaction of N(PPh2)3 ( 3 ) with silver chloride. All the compounds have been characterized, so far as possible, by IR, Raman, 1H NMR, 31P{1H} NMR, 13C{1H} NMR and mass spectroscopy.  相似文献   

9.
Synthesis and Structure of (Ph3PAu)3Mn(CO)4 Photolysis of (Ph3PAu)Mn(CO)5, Ph3PAuN3 and Ph3PAuNCO yields (Ph3PAu)3Mn(CO)4 ( 1 ). 1 crystallizes in the monoclinic space group P21/n with a = 1 031.3(1); b = 3 095.2(3), c = 3 386.3(3) pm; β = 97.58(3)°; Z = 8. The crystal structure contains two symmetry independent clusters 1 of the same geometry. Their inner core MnAu3 forms a rhombus with distances Mn? Au of about the same lengths between 258.4(4) and 262.0(4) pm. The distances Au? Au range from 276.6(2) to 281.3(2) pm. The bonding in 1 is discussed and compared with those of (Ph3PAu)3Co(CO)3 having the same total number of electrons but a tetrahedral framework.  相似文献   

10.
Lithiumphthalocyanines: Synthesis, Properties, and Crystal Structure of Bis(triphenylphosphine)iminiumphthalocyaninatolithates with Different Conformations of the Cation Reaction of tri(n-dodecyl)n-butylammoniumphthalocyaninatolithate, (TDBA)[LiPc2?] with bis(triphenylphosphin)iminiumbromide, (PNP)Br in dichloromethane yields (PNP)[LiPc2?]. It crystallizes in the triclinic space group P1 as dichloromethane solvate ( 1 ) and in the monoclinic space group P21/n as hydrate ( 2 ). The crystal structures of ( 1 ) and ( 2 ) are reported. Each salt contains two crystallographically slightly different discrete [LiPc2?]? anions, in which the square-planar coordinated Li+ cation is centered within the planar Pc2? ligand (Dav.(Li? Niso) = 1.945 Å). There are three different conformations for the (PNP) cation: ( 1 ) only contains the bent conformer (dav.(P? N) = 1.575 Å; φ(P? N? P) = 140.8°), while in ( 2 ) an hybrid (dav.(P? N) = 1.562 Å; φ(P? N? P) = 158.1°) and the linear conformer (dav.(P? N) = 1.547 Å; φ(P? N? P) = 176.8°) are present. The very soluble, blue-green salts melt at 265°C without decomposition. In accordance with cyclovoltammetric data thin films of (PNP)[LiPc2?] are oxidized by NO2 or Br2 to yield brown violet [LiPc?]. The electronic absorption spectra and the vibrational spectra are discussed.  相似文献   

11.
Metal Derivatives of Molecular Compounds. III. Molecular and Crystal Structure of Lithium bis(trimethylsilyl)phosphide · DME and of Lithium dihydrogenphosphide · DME Lithium bis(trimethylsilyl)phosphide · DME 1 prepared from tris(trimethylsilyl)-phosphine and lithium methanide [2, 4] in 1,2-dimethoxyethane
  • 1 1,2-Dimethoxyethan (DME); Tetrahydrofuran (THF); Bis[2-(dimethylamino)ethyl]methyl-amin (PMDETA).
  • , crystallizes in the orthorhombic space group Pnnn {a = 881.1(9); b = 1308.5(9); c = 1563.4(9) pm at ?120 ± 3°C; Z = 4 formula units}, lithium dihydrogenphosphide · DME 2 [10] prepared from phosphine and lithium- n -butanide in the same solvent, in P2 1 2 1 2 1 {a = 671.8(1); b = 878.6(1); c = 1332.2(2) pm at ?120 ± 3°C; Z = 4 formula units}. X-ray structure determinations (R w = 0.036/0.045) show the bis(trimethylsilyl) derivative 1 to be dimeric with a planar P? Li? P? Li ring (P? Li 256 pm; Li? P? Li 76°; P? Li? P 104°), and the dihydrogenphosphide 2 to be polymeric with a linear Li? P? Li fragment (P? Li 254 to 260 pm; Li? P? Li 177°; P? Li? P 118°). The shortened P? Si distance (221 pm) of compound 1 and the structure of the PH 2 group in 2 are discussed in detail. Lithium obtains its preferred coordination number 4 by a chelation with one molecule of 1,2-dimethoxyethane (Li? O 202 to 204 pm).  相似文献   

    12.
    On the Crystal Structures of CH3PF2H+AsF6? and CH3PF2H+SbF6? and a simple Method for Preparation of CH3PF2 A simple method for preparation of CH3PF2 from CH3PCl2 is reported. The phosphonium salts CH3PF2H+MF6? are obtained by the reaction of CH3PCl2 with superacidic systems HF/MF5 (M = As, Sb). CH3PF2H+SbF6? crystallizes in the space group P1 with a = 548.4(4) pm, b = 695.5(8) pm, c = 960.2(9) pm, α = 94.68(5)°, β = 97.19(6)°, γ = 94.41(6)° and Z = 2. CH3PF2H+SbF6? crystallizes in P1 with a = 554.3(3), b = 724.2(4), c = 970.4(5), α = 94.73(4)°, β = 96.14(5)°, γ = 95.30(4)°.  相似文献   

    13.
    C–H-Activation: Syntheses and Properties of Acetonato( C )-acidophthalocyaninato(2–)metallates(III) of Rhodium and Iridium; Crystal Structure of Tetra(n-butyl)ammonium Acetonato( C )azidophthalocyaninato(2–)iridate(III) Phthalocyaninato(2–)metallate(I) of rhodium and iridium reacts with carbonyl substrates like acetone or acetylacetone and halides or pseudohalides forming acetonato(C)- or acetylacetonato(C)acidophthalocyaninato(2–)metallates(III), that are isolated as tetra(n-butyl)ammonium complex salts (nBu4N)[M(R)(X)pc2–] (M = Rh, Ir; R = aC, acaC; X = Cl, I, N3, SCN/NCS). (nBu4N)[Ir(aC)(N3)pc2–] · 0,25(C2H5)2O · 0,5 CH2Cl2 crystallizes in the triclinic space group P1 with cell parameters a = 16.267(8) Å, b = 17.938(3) Å, c = 18.335(4) Å, α = 74.77(2)°, β = 73.73(3)°, γ = 84.25(3)°, V = 4954(3) Å3, Z = 4. There are two crystallographically independent anions, differing by the orientation of the azido ligand either towards an isoindole group or a Naza bridge of the phthalocyaninate, while the σ-C bonded acetonate is always oriented towards an isoindole group (gauche and ecliptical configuration). The Ir–C distances are 2.12(1) and 2.14(1) Å. Due to the trans influence of the acetonate-C atom the Ir-azide-N distances of 2.22(1)/2.24(1) Å are longer than expected. The electrochemical properties and the optical, vibrational, and 1H-NMR spectra are discussed.  相似文献   

    14.
    trans -Bis(triphenylphosphine)phthalocyaninato(2–)rhenium(II): Synthesis, Properties, and Crystal Structure Dirheniumheptoxide reacts with phthalodinitrile in boiling 1-chloronaphthalene and subsequent reprecipitation of the green raw product from conc. sulfuric acid to yield an oxo-phthalocyaninate of rhenium, which is reduced by molten triphenylphosphine forming dark green trans-bis(triphenylphosphine)phthalocyaninato(2–)rhenium(II), trans[Re(PPh3)2pc2–]. The latter crystallizes triclinic in the space group P 1 with the cell parameters as follows: a = 11.512(2) Å, b = 12.795(2) Å, c = 12.858(2) Å, α = 64.42(2)°, β = 79.45(2)°, γ = 72.74(1)°; V = 1628.1(5); Z = 1. Re is in the centre of the (Np)4 plane (Np: N1, N3) and coordinates two triphenylphosphine ligands axially in trans position. The average Re–Np and Re–P distances are 2.007(1) and 2.516(3) Å, respectively. Despite the many extra bands the typical B, Q and N regions of the pc2– ligand are observed at ca. 16500, 28900/32900 and 35300 cm–1. A weak band group at ca. 8900 cm–1 is attributed to a trip-multiplet transition, another one at ca. 14500 cm–1 to a P → Re charge transfer. The vibrational spectra are dominated by internal vibrations of the pc2– ligand. The very weak intensity of the IR bands at 905 and 1327 cm–1 are diagnostic of the presence of ReII.  相似文献   

    15.
    Summary 5-Fluoro-uracil (1) reacts with chloro-diphenylphosphane to 5-fluoro-N(1), N(3)-bis(diphenylphosphanyl)uracil (3) which was characterized by X-ray crystallography, IR, and mass spectra.19F,31P{1H},13C{1H}, and1H NMR spectra indicate that3 rearranges inTHF solution to some extent to the tautomeric 5-fluoro-O(2), O(4)-bis(diphenylphosphanyl)uracil (4). If the solvent contains traces of water, Ph2P(O)-PPh2 (6) and uracil derivatives are formed by hydrolysis.
    Herrn Professor Dr.Walter Siebert zum 60. Geburtstag gewidmet.  相似文献   

    16.
    Synthesis and Structure of Mo2NCl7 The reaction of VN with MoCl5 at 175 °C in a sealed glass ampoule yields the molybdenum(V) nitride chloride Mo2NCl7 in form of air sensitive black crystals with the triclinic space group P1¯ and a = 905.7(8); b = 975.4((6); c = 1283.4(8) pm, α = 103.13(4)°; β = 109.83(5)° und γ = 98.58(5)°. The crystal structure is built up from dinuclear units [Mo2N2Cl7]3— and [Mo2Cl7]3+, which are connected by asymmetric nitrido bridges to form endless chains. Within both dinuclear units the Mo atoms are bridged by three Cl atoms resulting in a Mo‐Mo distance of 349.2(3) pm in the unit [Mo2N2Cl7]3—. In case of [Mo2Cl7]3+, however, a shorter Mo‐Mo distance of 289.4(3) pm is observed, which can be interpreted by a single bond. Correspondingly a reduced magnetic moment of 0.95 B.M. per Mo atom is observed.  相似文献   

    17.
    Synthesis and Properties of (Acido)(nitrosyl)phthalocyaninato(2–)ruthenium (Acido)(nitrosyl)phthalocyaninato(2–)ruthenium, [Ru(X)(NO)pc2–] (X = F, Cl, Br, I, CN, NCO, NCS, NCSe, N3, NO2) is obtained by acidification of a solution of bis(tetra(n-butyl)ammonium) bis(nitro)phthalocyaninato(2–)ruthenate(II) in tetrahydrofurane with the corresponding conc. mineral acid or aqueous ammonium salt solution. The nitrite-nitrosyl conversion is reversal in basic media. The cyclic and differential pulse voltammograms show mainly three quasi-reversible one-electron processes at 1.05, –0.65 and –1.25 V, ascribed to the first ring oxidation and the stepwise reduction to the complexes of type {RuNO}7 and {RuNO}8, respectively. The B < Q < N regions in the electronic absorption spectra are still typical for the pc2– ligand, but are each split into two strong absorptions (14500/16500(B); 28000/30500(Q); 34500/37000 cm–1(N)), whose relative intensities strongly depend on the nature of the axial ligand X. In the IR spectra is active the N–O stretching vibration between 1827 (X = I) and 1856 cm–1 (F), the C–N stretching vibration at 2178 (X = NCO), 2072 (NCS), 2066 (NCSe), 2093 cm–1 (CN), the N–N stretching vibration of the azide ligand at 2045 cm–1, the fundamentals of the nitrito(O) ligand at 1501, 932, and 804 cm–1, and the Ru–X stretching vibration at 483 (F), 332 (Cl), 225 (Br), 183 (I), 395 (N3), 364 (ONO), 403 (CN), 263 (NCS), and 231 cm–1 (NCSe). In the resonance Raman spectra, excited in coincidence with the B region, the Ru–NO stretching vibration and the very intense Ru–N–O deformation vibration are selectively enhanced between 580 and 618 cm–1, and between 556 and 585 cm–1, respectively.  相似文献   

    18.
    Synthesis and Properties of Bis(tetra(n-butyl)ammonium)μ-Carbido-di(halophthalocyaninato(2–)ferrates(IV)); Crystal Structure of Bis(tetra(n-butyl)ammonium) μ-Carbido-di(fluorophthalocyaninato(2–)ferrate(IV)) Trihydrate μ-Carbido-di(pyridinephthalocyaninato(2–)iron(IV)) reacts with tetra(n-butyl)ammonium halide (nBu4N)X) in solution (X = F) or in a melt (X = Cl, Br) to yield bis(tetra(n-butyl)ammonium μ-carbido-di(halophthalo-cyaninato(2–)ferrat(IV)). The fluoro-complex salt crystallizes as a trihydrate monoclinically in the space group P121/n1 with the following cell parameters: a = 15.814(1) Å; b = 22.690(5) Å; c = 25.127(3) Å; β = 98.27(1)°, Z = 4. The Fe atoms are almost in the centre (Ct) of the (Niso)4 planes (Niso: isoindoline-N atom) with a Fe–Ct distance of 0.053(1) Å. The average Fe–Niso distance is 1.939(4) Å, the Fe–(μ-C) distance 1.687(4) Å and the Fe–F distance 2.033(2) Å. The Fe–(μ-C)–Fe core is linear (179.5(3)°). The pc2-ligands are staggered (φ = 42(1)°) with a convex distortion. The asymmetric Fe–(μ-C)–Fe stretch (in cm–1) is observed in the IR spectra at 917 (X = F), 918 (Cl) and 920 (Br) and the symmetric Fe–(μ-C)–Fe stretch at 476 cm–1 in the resonance Raman spectra. The IR active asymmetric Fe–X stretch (in cm–1) absorbs at 336 (X = F), 203 (Cl), 182 (Br), respectively.  相似文献   

    19.
    Bromosulfenyl(trihalogeno)phosphonium Salts Cl3?nBrnPSBr+AsF6? (n = 0 – 3) and Cl3PSBr+SbF6? — Oxidative Bromination of Thiophosphorylhalides The bromosulfenyl(trihalogeno)phosphonium salts Cl3?nBrnPSBr+AsF6? (n = 0 – 3) and Cl3PSBr+SbF6? are prepared by oxidative bromination of the corresponding thiophosphorylhalides with Br2/MF5 (M = As, Sb) and characterized by vibrational and NMR spectroscopy.  相似文献   

    20.
    Synthesis and Structures of γ-Halopropyl-octa(silasesquioxanes) As a more rapid and versatile synthetic approach, we have studied the FeCl3-catalyzed hydrolytic polycondensation of suited trichlorosilanes in a biphasic system which yields e.g. the new octa(silasesquioxane) (BrCH2CH2CH2)8Si8O12.  相似文献   

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